Our antique PowerVault tape drive failed. I asked to find a replacement. After extensive research I recommended Unitrends. Two Recovery-823 devices were approved and I implemented the first one, with the second soon to follow.

I am looking at replacing our current CX700 with a new SAN. I have been looking at a dell PS6000E and a EMC/DELL CX4. The problem i am running into is we are getting these units from dell and one rep says the Equallogic iSCSI will be perfect while another dell rep say it will not be fast enough with the sata drives. The PS6000E will have 16 1TB sata drives 7.2K. the EMC will have 5 10K sas and 12 1TB SATA 7.2k drives. I am torn because dell produces both of these products and they are giving me conflicting answers.

Where should i start to determine which is correct with out dell helping, since they are telling me two different things i am stuck.

Im bound by a budget that was not expecting an upgrade and really need help. If anyone has experience with either units any adivce or info would help.

There will be a handfull of SQL databases on it along with exchange and file sharing.

We just went through this in December. Both the EMC and the EqualLogic are solid brands. The major difference between the two is their purchasing paradigm. EMC sells their system components a la carte, while EqualLogic sells their systems as whole units. Value-wise, EqualLogic is more expensive up front, but is a better value between the two, because all the “Premium Features” are already available. No license upgrades to unlock replication, snap-shots, etc. EMC is cheaper up front but every feature you need to add later will cost you and cost you big.

iSCSI works just fine for most environments and as you add EqualLogic chassis together the overall throughput is relative. 1 box add 3 Mbps, 2 = 6 Mbps and so on. I believe they offer, or soon will be, 10GbE which blows FC away and set the stage for FCoE (Fibre Channel over Ethernet) and will stack the same way as their bonded 1GbE. With MPIO (Multi-Path I/0) the FC/iSCSI argument is moot. iSCSI is FAR easier to manage than FC (we got rid of our FC because it was such a bitch to manage).

The real difference functionally between the two systems is going to be your drive options. With SQL your IOPS (I/O per second) will be your critical metric for choice. Storage subsystems are the #1 bottleneck in SQL environments and the majority of that contention is from low IOPS performance not throughput.

SATA drives only get about 75 IOPS per drive. So 16 SATA drives will only give you 1,200 IOPS. SATA is good for mass storage, but horrible for SQL environments.

10K SAS drives get about 120 IOPS per drive. So your 5 x 10K drives are only going to give you 600 IOPS. Not a good choice by your Dell rep regardless of the system they’re trying to sell.

What you need to do is monitor your read and write IOPS and determine what your minimal IOPS needs are with room for heavy loads as there is a performance curve as you approach your maximum available IOPS.

Key items in a good SAN are:

RAID Cache - More is better. Cache gets your write requests out of the way of your read requests which speeds up performance hugely.

Storage Processor/Controller count - Always get two. That way if one storage controller fails the other keeps running.

Manageability - Don’t underestimate how important being able to quickly manage a system is. EMC has the industries worst interface. EqualLogic’s is unparalleled in the commercial market.

All this being said, have you considered an open-source initiative, such as OpenFiler, FreeNAS or even SUN’s open-storage lineup? You can build highly available storage systems at nearly 1/10th the cost of an “Enterprise” SAN and actually outperform the “Enterprise” stuff.

9 Replies

For your production machines, I'd stay with at least 10K RPM SAS drives. You need the speed and the durability of these drives. SATA just doesn't have that.

You might want to consider a SAM-SD with SAS and SATA mixed in. Also buy support for OpenFiler and you're in about the same boat as the EMC/Equalogic stuff and a fraction of the cost.

OpenFiler is actually free, but for your production boxes I wouldn't go with it unless you purchase the support with it too. Even then, you have to measure your level of bravery versus the enormous cost you're about to pump out. You can prolly get a SAM-SD with the mix of drives you want for $6 or $7K. How much is that EMC gonna run you? $50K? More?

Well your going to be limited by drives speeds way before limited by media (Fiber Channel or iSCSI)

If you storing just basic data use the SATA drives. Cheaper for more space.

If you hosting exchange mailboxes, SQL datbases or whatever buy the fast SAS drives. I'd 15k if you can over the 10k's

I image you can mix or buy multiple enclosures with Dell's solutions just like all the others. Some you can even mix drive speeds and sizes in the same enclosure or have multiple data packs int eh same enclosure to save cost (Xiotech)

I am no Dell fan and have never used there SAN devices or know any background about them. That being said if I spoke with 2 tech for any company about a product and received 2 totally different answer I wouldn't even bother posting on a forum I would just pass them over. I have not tollerance for inconsistencies!

Compellent has agreat FC solution. Easy to use, great service and support

HP lefthand iSCSI is pretty easy on the wallet and might work great depending on your company. By no means a traditional SAN. Plus no need for a bunch of extra HBA's and fiber cables

Xiotech has some interesting hardware with there ISE units but software demo was dissapointing.

Do you have more details on what kind of loads the array will see? A handful of DB's and Exchange can mean different things if we're talking about a couple GB of SQL data and 50 mailboxes vs TB's of SQL data and 1,000+ mailboxes.

Do you have more details on what kind of loads the array will see? A handful of DB's and Exchange can mean different things if we're talking about a couple GB of SQL data and 50 mailboxes vs TB's of SQL data and 1,000+ mailboxes.

We have around 26 SQL databases that are very small. Most of them are under 3 or 4 GB, i do have one or two that are around 40 t0 50GB, we have not reached the TB level yet for anything. Exchange is about 350 mailboxes and will be near 600 at the most.

The biggest problem i might have would be our current software applications here run from the network.

The conflicting advice is because Dell bough both EMC and Equalogic and I belive they both still operate as different divisions internally so they're competing against each other. You should have a Dell account manager who should be impartial in the middle somewhere.

Personally I would say the cost of FC isn't justified, stick with iSCSI, however 'd also say you need the SAS disks, preferrably 15K - there are 3 Equalogic PS6000 boxes that handle SAS drives - the 6000XV will handle the 15K SAS disks. I would imagine that would work out cheaper than the EMC.

Personally I use an Axstor iSCSI SAN, but Dell were quoting at the time of purchase, and similarly they told you about all the options, but wouldn't actually say EMC Is better than Equalogic for your situation - or vice versa.

EMC has came back to be with an alternate setup to fix this issue. I have a fixed budget of 56K or so. I told our dell rep that neither setup would work and i would need something with a little more horse power. So this is what they have put together:

CX4-120 that has iSCSI and FC (iSCSI for now untill i get the FC HBA for the blade)

15X450GB 15K SAS (databases / email / apps)

5 to 8 1TB 7.2K SATA (file sharing and what not)

They have managed to get this for approx 55K. Still waiting for the official quote, but i think this is a much better solution than the PS6000E (55K for this), both have 5 year 24X7 mission critical support, any thoughts?

We just went through this in December. Both the EMC and the EqualLogic are solid brands. The major difference between the two is their purchasing paradigm. EMC sells their system components a la carte, while EqualLogic sells their systems as whole units. Value-wise, EqualLogic is more expensive up front, but is a better value between the two, because all the “Premium Features” are already available. No license upgrades to unlock replication, snap-shots, etc. EMC is cheaper up front but every feature you need to add later will cost you and cost you big.

iSCSI works just fine for most environments and as you add EqualLogic chassis together the overall throughput is relative. 1 box add 3 Mbps, 2 = 6 Mbps and so on. I believe they offer, or soon will be, 10GbE which blows FC away and set the stage for FCoE (Fibre Channel over Ethernet) and will stack the same way as their bonded 1GbE. With MPIO (Multi-Path I/0) the FC/iSCSI argument is moot. iSCSI is FAR easier to manage than FC (we got rid of our FC because it was such a bitch to manage).

The real difference functionally between the two systems is going to be your drive options. With SQL your IOPS (I/O per second) will be your critical metric for choice. Storage subsystems are the #1 bottleneck in SQL environments and the majority of that contention is from low IOPS performance not throughput.

SATA drives only get about 75 IOPS per drive. So 16 SATA drives will only give you 1,200 IOPS. SATA is good for mass storage, but horrible for SQL environments.

10K SAS drives get about 120 IOPS per drive. So your 5 x 10K drives are only going to give you 600 IOPS. Not a good choice by your Dell rep regardless of the system they’re trying to sell.

What you need to do is monitor your read and write IOPS and determine what your minimal IOPS needs are with room for heavy loads as there is a performance curve as you approach your maximum available IOPS.

Key items in a good SAN are:

RAID Cache - More is better. Cache gets your write requests out of the way of your read requests which speeds up performance hugely.

Storage Processor/Controller count - Always get two. That way if one storage controller fails the other keeps running.

Manageability - Don’t underestimate how important being able to quickly manage a system is. EMC has the industries worst interface. EqualLogic’s is unparalleled in the commercial market.

All this being said, have you considered an open-source initiative, such as OpenFiler, FreeNAS or even SUN’s open-storage lineup? You can build highly available storage systems at nearly 1/10th the cost of an “Enterprise” SAN and actually outperform the “Enterprise” stuff.

Thanks for the information you provided about the SAN's, this helped my decision to go for equallogic. Our dell partner is going to supply us with a PS6000XV with 16 drives that are running 15K SAS at 600 GB for the same price as the PS6000E with 1TB SATA. I am very happy with this purchase.

The next thing im goign to have to figure out is how to move our exchange server to the new SAN. that is goign to be a whole different story by its self. We have an exchange active/passive cluster that i need to break and move to a new blade server with out the clustering, planning on using ESX with HA to replace the clustering. Let the research begin.

Although we went with the EMC (up-front cost was the killer with finance), I love the EqualLogic stuff and would recommend them hands down over EMC any day of the week. They gave us a unit to demo and I set it up myself in about 2 hours. It took the EMC “engineer” 2 1/2 days to do the same thing. Never underestimate the cost of being able to manage something without a phone call to the vendor. And after using several SANs now, I have to say bar-none, EQ has THEE best interface on the market. The fact that everything is just there makes it even better.

If you’re looking into HA and concerned about cost, consider not using ESX. While they have the most offerings right now their cost is outrageous. And the competition is closing in on their level of functionality rapidly. You can get about 90+% of VMWare’s functionality out of other vendors at 1/10th or better the cost.

Citrix XenServer offers FAR more than ESXi for free and the HA stuff is only $2500.00 or $5000.00 per server, depending on which level of support you want.

If you feel like digging a bit into Linux Xen will give you the whole package for the cost of learning how to use it. And there are GUI management suites for it so, while you still have the command line as an option, you can do it all through a gui. Convirt, oVirt and enomaly to name a few; all three being free. Xen has also released the Xen Cloud Platform (not production ready yet, but soon I expect) that’s going to compete and compare directly to the VMWare stuff.

If you are willing to go the KVM route Red Hat now sells RHEV (Red Hat Enterprise Virtualization) built on KVM. While KVM is not as recognized as Xen and doesn’t have as many features Red Hat is selling it for a very reasonable amount. Knowing their reputation, they wouldn’t be selling it if it couldn’t compete. Plus, again they’re selling it at a reasonable cost with actual support for $500/CPU Socket or $700/CPU Socket depending on your support requirements.